Leaf litter decomposition and its drivers differ between an invasive and a native plant: Management implications

Abstract

Litter decomposition is a key process of the carbon cycle in terrestrial and aquatic ecosystems. The dominant conceptual model of litter decomposition assumes that environmental conditions, litter traits, and decomposer composition control litter decomposition in a decreasing order, yet whether this hierarchical model applies to both invasive and native plant species is unknown. Here, by comparing a widespread invasive plant and its native counterpart in Chinese coastal saltmarshes, we aimed to examine whether the hierarchy of factors controlling litter decomposition varies with plant species in the face of plant invasions. Leaf litter of invasive Spartina alterniflora and native Phragmites australis was collected across an 18° latitudinal range to capture wide variation in litter traits. These leaf litter samples were transported to three saltmarsh sites of different latitudes and were incubated in litterbags varying in mesh size (0.1, 2, and 5 mm) to manipulate decomposer composition. After 90‐day incubation, we found a parallel latitudinal pattern in leaf litter decomposition rate (k) between S. alterniflora and P. australis regardless of saltmarsh site and mesh size. Nonetheless, the k value of S. alterniflora was 2.2‐fold higher than that of P. australis. Moreover, there was a shift in the hierarchy of factors controlling k values between S. alterniflora and P. australis: environmental conditions (climate and soil) dominated other factors in P. australis, whereas litter traits contributed more than environmental conditions in S. alterniflora. Overall, our findings show that leaf litter decomposition and its dominant controlling factors across broad geographical ranges can vary with plant invasions, having important implications for managing invasive plants in the context of conserving coastal blue carbon.

Perspectives of invasive alien species management in China

“…In addition to the traditional impacts, such as competition, predation, and disease transmission, IAS can also influence key ecological processes during their invasions. For example, Cheng et al (2023) conducted field surveys across a wide 18° latitudinal range and a 90‐day incubation experiment. They found that variations existed in leaf litter decomposition and its dominant controlling factors between native and invaded plant communities.…”

Lessons from the invasion of Spartina alterniflora in coastal China

“…S. alterniflora has reduced biodiversity in China's coast by displacing native salt marsh plants, encroaching into mangrove gaps, and transforming mudflat habitats into salt marshes (Li et al, 2022; Zhang et al, 2012). S. alterniflora has homogenized soil communities (Zhang et al, 2019), has a higher leaf litter decomposition rate than the native Phragmites australis across a range of latitude (Cheng et al, 2022), and has driven losses in habitat and food resources of migratory birds (Gan et al, 2010). Its spread has destroyed aquaculture industries that were based on farming mudflat species such as razor clams.…”

Genotype diversity enhances invasion resistance of native plants via soil biotic feedbacks

“…We here used an experimental system in a saltmarsh plant community to investigate the effect of genotypic diversity of a foundation native species Scirpus mariqueter Tang & Wang on the growth of Spartina alterniflora Loisel., an aggressive perennial grass that has invaded saltmarshes globally (Cheng et al, 2024). The native S. mariqueter is a perennial sedge that is endemic to China and is mainly distributed in saltmarshes of the Yangtze River estuary and Hangzhou Bay (Sun et al, 2001), but has experienced severe population decline and loss of genetic diversity because of land-use change and invasion by S. alterniflora (Ma et al, 2009).…”